If you have a good moveset for Heliolisk, post an answer below and upvote the best ones. Remember, this is for competitive movesets, not in-game. Ability, EVs etc should be included. Make sure to read all the guidelines here.

With a quite nice base 109 speed, in coherence with an offensive typing and abilities that complement both Rain and Sand, Heliolisk makes a fine choice for your non-ability weather inducer. For the most part, the items, abilities, and moves that work best together are lined up with eachother, though moveslots three and four are more open to variance. Thunder and Thunderbolt are obligatory STAB that helps deal with opposing water types, known to give both sand and rain issue. The second slot goes to the weather set up of choice. Third, surf is best left for rain, as it has far more power and is more reliable than Focus Blast, and even in sand the accuracy may make it the better choice, but Focus Blast is nice for nailing tyranitar and ferrothorn among other things. Finally, Volt Switch allows for some hefty damage to be dealt while the main weather sweeper comes in, but it should be noted that Dark Pulse, in addition to reliable nailing the great threats Aegislash, Shadow Tag Chandelure and Mega-Gengar, is also Heliolisk's only reliable way of hitting Latios/Latias for solid damage, though all three outspeed it.

Other options include Grass Knot for nailing heavier round types and water/grounds as well as tyranitar, and typically, a rain boosted surf will outdamage an se HP Ice, while also being more useful overall. Unforunately, Heliolisk does not learn Sunny Day, as otherwise, a set similar to the one above with Solar Power would be viable.

It's got an unnecessary Normal typing for some reason, meaning it's weak to Mach Punch. Doesn't help that it has a base 52 Defence as well. In any case, it's got a decent movepool to utilise with a nice base 109 sp. atk & speed.

Heliolisk will work well on rain teams and in doubles w/ Surf from Dry Skin. For a doubles set, replace Volt Switch w/ Protect instead. And then finally a coverage move of your choice.

This guy will be best running a Scarf set imo due to his base speed sitting around 109, putting him in a fantastic speed tier. Thunderbolt is your reliable, fairly hard hitting STAB. Volt Switch is STAB as well to help you escape bad situations. Surf is coverage getting off good damage on Ground types. HP Ice gets Grass and Dragon types the other moves can't.

This is basically the set I would suggest, so I won't be making my own answer and be lame like that. I will however suggest something to use in place of Focus Blast: Either HP Ice or a less ideal HP Fire.

Thunderbolt/VS and Surf are going to be the moves of choice to deal with most foes. However, these two types do not cover Grass and Dragon type Pokemon. Focus Blast does little to patch up this fault, leaving Leavanny (who is indeed a consideration thanks to Sticky Web), Amoonguss, and potentially will leave it unable to handle Dragalge, Trevenant, and Gourgeist.

The rain Sweeper

Basically the same moveset for the 3 of us. The normal typing adds a weakness to fighting, but otherwise, it adds a resistance and thus immunity to both Jellicent's STAB when Dry Skin is your ability. This should abuse Drizzletoad. OK, we are not gonna see this much in OU and near never in Ubers, but who knows... Thunder > Thunderbolt and the other options, for the extra power, and the ability to abuse Rain. Volt Switch maybe be used on weak Water Pokémon, I mean frail ones, like Starmie, thus OHKOing it and switching to prepare against a threat. Surf is also abusing Rain to double its power, and can OHKO Heatran, not the specially defensive one of course. Grass Knot is here to smash the OU, full of obese Pokémon, while Dark Pulse can be an answer to Alakazam, Aegislash, Gengar and so-on.

Basically, lanturn sets up rain. Heliolisk paralyzes (or poisons) opponents, then phases them out, proceeding to do the same to the rest of the opponent's Pokemon. Mist prevents stats being lowered. Heliolisk and Lanturn heal each other with surf, and slowly whittle away the opposing team. Blizzard covers ground and grass types. Thunder for those Pokemon that just won't faint.

Pretty much one of my favorite sets for sunny teams and works well by itself if your sunny day provider or Drought member is knocked out. So it's pretty much you should run either Charizard Y or a Ninetales if you want a different mega on your team.

-Thunder if you are using him in rain , Thunderbolt if not cause missing ticks me off. :(.

-Surf : This thing can surf :D Covers ground weakness , kills steel types that since nothing else hits it in this set. Nice for ingame use as well.

-Last slot is situational @.@. Grass knot works because all rock types are fat making it out damage surf. Usually. Dark pulse is super effective against ghosts. Lots of people are saying focus blast but.. I personally hate it. Missing all day n night. BUT PERSONALLY MY SUGGESTION IS.. Hyperbeam? :l. It allows you to use the normal type for something and well fi you are going down go down with a 100 accuracy BANG! :D

Dry Skin + Rain Dance + Leftovers is the best combo on Heliolisk, imho. With the Rain set up I can heal off most of the Sub damage. This set can wall pretty much any special sweeper with a SE move, though probably not any Megas or Legends. But she walls pretty well.

EVs highlight Special Defense and Speed. 301 speed is enough to outspeed the bulkier sweepers and lets me catch a few already-fast-and-not-investing-in-speed-evs sweepers. Otherwise Heliolisk can usually tank a hit before setting up a Sub.

Once I have a Sub up, I have one free turn to do as I please. I usually set up Rain Dance ASAP, since the recovery is amazing on Heliolisk due to her low HP.

Thunder wrecks in the Rain, having a whopping 165 base power after STAB. It's the strongest Electric type attack and this set only works in the Rain so why not.

Psych Up is probably a questionable move, but I just picked it and it worked. It works well against Pokemon like Gardevoir (non-Mega), who set up with Calm Mind first. One time a dude got like +3 SAtk and SDef on a Gardevoir. I was faster, so I was able to Psych Up and tank the blow, then proceed to damage the Gardevoir like there were no stat changes (due him being +3 SDef and me being +3 SAtk).

The problem with this set is of course the Ground type, Megas/Legends, anything that resists Electric and Physical or Mixed sweepers. I keep this set away from such things, and it works pretty well. Not the best set on Heliolisk but a good one if you ask me.

Rules: Switch out when nasty ground, fighting, grass and dragon types appear out of enemy team
Steps: Start with sandstorm to raise evasion then always use electrify before you use thunder wave. After your done with those moves spam the wild charge.
The bright powder combined with sand veil + sandstorm will make your opponents moves miss the wild charge or thunderbolt will deal damage at the enemy team as much as possible

⋅The second slot goes to Rain Dance - heals in rain, Thunder never misses and powers up Surf.

⋅The third slot goes to Hyper Voice - 90 base power + stab (might be less useful but I like it (also, it's only obtainable through OrAs move tutor))
OR
Surf has a base power of 90 and is powered up in rain, hits multiple targets and great for ground coverage.

I personally don't like choice specs as it restricts you to one move, so I prefer to give Heliolisk Wise Glasses to boost its special moves by 10%. If you find Hyper Voice useless, you could easily replace it with Surf.

Also, this moveset is perfect for double battles. I would personally Pair it up with a Volt Absorb Lanturn. Lanturns Surf(powered up by Rain Dance) heals Heliolisk and Heliolisks Parabolic Charge heals Lanturn in return.